Two Marin County prosecutors who won guilty verdicts and the death penalty against a Northern California serial killer last year have received statewide honors for their work.

Deputy District Attorneys Dori Ahana and Rosemary Slote were named outstanding prosecutors of the year by the California District Attorneys Association. Ahana and Slote prosecuted Joseph Naso, 80, who is now on death row at San Quentin State Prison.

Marin County District Attorney Ed Berberian announced the award Friday during a boisterous staff gathering at the Civic Center. He also recognized Inspector Michael McBride, the primary district attorney's investigator on the case, and volunteer assistant Mary Bramblett.

Berberian noted that the state award was created in 1977 to honor two Marin prosecutors — Jerry Herman and Terrence Boren — for their work on the "San Quentin Six" murders that stemmed from a prison riot. Herman went on to become district attorney, while Boren became a judge in Marin Superior Court.

"Thirty-seven years later, that recognition has come back to Marin County," Berberian said.

In brief remarks, Ahana and Slote said they would accept the award on behalf of the entire office when the annual ceremonies are held in June in Newport Beach.

"It was a team effort," Slote said.

Naso, a retired property manager and photographer, was sentenced to death in November after nearly three years of court hearings that included a lengthy trial in Marin Superior Court. He was tried in Marin for all the murders, including ones that occurred in other counties.

During the guilt phase of the trial, he was convicted of murdering four women between 1977 and 1994 and dumping their bodies on rural roads in Marin, Yuba and Contra Costa counties.

During the death penalty phase of the trial, Ahana and Slote also presented evidence that Naso also killed two other women, a former Naso tenant whose body washed up in Tiburon in 1981, and a nomadic Bob Dylan groupie who was killed in 1992 in or near Nevada County.

Prosecutors alleged that the women represented six of 10 unnamed women on a list Naso maintained to document his murders. Investigators still hope to determine who the other four women were.

Naso, who represented himself at the trial, maintained that the prosecution had failed to prove its case and that evidence was planted. He said the prosecution "was kind of like a hate crime against me."

The California District Attorneys Association award for Ahana and Slote is in the category for counties with populations under 450,000. The award for large counties went to Eric Smith, a Kern County gang prosecutor who spent 236 days in trial last year on eight cases, including seven murders, the association said.